Process for the preparation of monocyclic ketones and their alkyl derivatives having more than nine ring members



Patented Feb. 19, 1929.

UNITED STATES PATENT OFFICE.

LEOIOLD RUZICKA, OF GENEVA, SWITZERLAND, ASSIGNOR TO M. NAEF & CO., OF

' GENEVA, SWITZERLAND, A COMPANY OF SWITZERLAND.

PROCESS FOR THE PREPARATION OF MONOCYCLIC KETONES AND THEIR ALKYL DE- RIVATIVES HAVING MORE THAN NINE RING MEMBERS.

No Drawing. Application filed November 19, 1926, Serial No. 149,538, and in Switzerland December 15, 1925.

eral manner forthe preparation of monocyclicketones having more than nine ring members and of their alkyl derivatives, from the dicarboxyclic acids having more than ten carbon atoms in a normal chain or from their alkyl derivatives, the metals-and the compounds of metals belonging to the rare earths 2 may advantageously be employed.

According to the present invention lantha- I cane-1.14-d1carboxylic acid is heated, prefnum which belongs to the said metals, or its compounds such as for instance lanthanum oxide are employed either alone or mixed with another metal or metal compound belonging to the said group.

. It is'also advantageous to use a mixture of several metals of the third or fourth group of the periodic system, these mixtures being obtained artificially or otherwise.

Mixtures of the above mentioned dicarboxylic acids or their alkyl derivatives, which are prepared from the pure acids or as they 'tion preferably in a vacuum' with lanthanum of natural musk and can therefore be used as I a perfume as well as a primary material for 75- preparing other interesting technical compounds. I

- Example 2.

3-methgl-tetradecane-1.14-dicarboxylic acid is heate up to above 300 to 500 degrees centrigrade and towards the end of the reac- I I I o u I o I i are obtamed mcertam technical methods or from natural products give, according to the prescntinvention, mixtures of the ketones or their alk -l derivatives, which, in this form, can also )8 employed in practice.

For obtaining the mentioned monocyclic ketones it is possible'to directly heat the acids or the acid anhydrides alone or in presence of metals or metal compounds at a comparatlvely high temperature, instead offirst transforming the corresponding dicarboxylic acids into salts. In this case the use of metals of the rare earths is also advantageous.

The ketones or their alkyl derivatives obtamed by the described process can be used as perfumes or as primary materials for the preparation of other technically important compounds.

" Example 1.

The lanthanum salt of 3-methyl-tetradeobtained therefrom is worked up by fractional distillation. The fraction distilling at from 100 to 150 C. at a pressure of 0.5 mm. are then treated with semic'arbazide or other reagent usually employed for isolating the wo+lmoi+scoi hydroxide in a quantity which does not suflice for completely converting theacid into thev normal salt. The product obtained is treated according to the method described in Example 1.

, Ema'mple 3.

.A mixture of the lanthanum and cerium salts of 4-methyl-tetradecane-1.M-dicarboxylic acid is heated and worked up as described in Example 1. The 4-methyl-cyclopentadecanone obtained boils at about C. (at 0.3

mm.) ,(gives a semicarbazone melting at about i and has a smell practically corresponding completely to that of natural musk and can therefore be used as perfume and for preparing other interesting technical compounds.

Example 4.

4-met-hyl-tetradecane-1.14-dicarboxylic acid is heated at about 300 to 500 C. and towards the end of the reaction preferably in a vacuum, with lanthanum oxide. The product obtained is worked up as described in Example 3.

Example 5.

The lanthanum salt of tetradecane-LM-dicarboxylic acid is heated and worked up as described in Example 1. The cyclo-pentadccanone is obtained which distills at about 120 C. (at 0.3 mm.) and melts at 63 C.

Example 6'.

Tetradecane-1.14-dicarboxylic acid is heated at about 300 to 500 (1, towards the end of the reaction preferably in vacuum, with lan-- thanumhydroxide. The distillate resulting therefrom is worked up as described in Example 5.

Example '7.

The anhydride of tetradecane-1.14-dicarboxylic acid is heated to about 300 to 500 C. towards the end of the reaction, preferably in a vacuum with lanthanum hydroxide and worked up as described in Example 5.

Example 8.

A lanthanum salt of tetra-1.14-dicarboxylic acid is prepared by partially neutralizing this dicarboxylic acid with sodium hydroxide and precipitating with lanthanum chloride. The resulting lanthanum salt is decomposed by heating and worked up as described in Example 5.

- Example .9.

The lanthanum salt of octadecane-1.18-dicarboxylic acid is heated preferably in a vacuum to about 300 to 500 and the resulting distillate is worked up by fractional distillation. The fraction distilling at from 140 to 180 C. (at 0.3mm) is then treated with semicarbazide or another reagent usually employed for isolating the ketones. The cyclononadecanone in a pure state can in this manner be isolated by treating the semicarbazone purified by crystallization from alcohol and melting at 184 C. This ketone boils at 160 C. (at 0.3 mm), melts at 72 C. and

has a smell which nearly corresponds to that of civetone. It can therefore be used as a perfume and as a primary material for preparing other interesting technical compounds; by oxidizing the cyclononadecanone with chromic acid heptadec-a-ne-1.17-dicarboxylic acid is formed.

Example 10.

A mixture of cyclopentadecanone and cyclohexadecanone is obtained by working up according to the method described in Example 1 a mixture of lanthanum and cerium salts of tetradecane-l.14-dicarboxylic and pentadecane -l.lo-dicarboxylic acids.

I claim:

1. A process for the preparation of monocyclic ketones having more than nine ring members comprising heating lanthanum salts of polymethylene-dicarboxylic acids, having more than ten carbon atoms in a normal LEOPOLD RUZIGKA. 

